While building Codegen, we took a detour to solve a problem that kept blocking our agents: making large-scale, structural changes to a codebase reliably. The answer was graph-sitter — an open-source library for programmatic codebase refactors, built on top of Tree-sitter.
Instead of nudging files one edit at a time, graph-sitter builds an in-memory graph of a codebase — functions, classes, imports, and their relationships — and exposes high-level APIs that match how engineers actually think about refactors and migrations. It became the foundation for our "act via code" thesis.
The thesis behind it
Links & milestones
Announcing an IDE purpose-built for codebase refactors.
Introducing graph-sitter as an open Python library for manipulating codebases.
The open-source repository (Apache 2.0).
Jay Hack, Founder